The most widely used measurements of Arctic ice extent are the daily satellite readings issued by the US National Snow and Ice Data Center, which is co-funded by NASA.

He also stated that:

For years, many have been claiming that the Arctic is in an ‘irrevocable death spiral’, with imminent ice-free summers bound to trigger further disasters. These include gigantic releases of methane into the atmosphere from frozen Arctic deposits, and accelerated global warming caused by the fact that heat from the sun will no longer be reflected back by the ice into space.

Judith Curry, professor of earth and atmospheric sciences at Georgia Institute of Technology in Atlanta, said last night: ‘The Arctic sea ice spiral of death seems to have reversed.’

All of which got me thinking. Why did David Rose speak to a professor of earth and atmospheric sciences when researching his article, rather than an expert on Arctic sea ice? Why, indeed, did he not speak to the man who originally coined the “Death spiral” metaphor? Seeking answers to these troubling questions amongst others, I called the National Snow and Ice Data Center in Boulder, Colorado. I enquired whether I might be able to speak with Mark Serreze, who is currently director of the NSIDC. Shortly after that Mark called me back and I was able to ask him a number of questions.

My first question was whether David Rose or anyone from the Mail on Sunday had been in touch with the NSIDC recently. The answer was “No”. Next I enquired whether the “Death spiral” story was apocryphal or not. Mark told me he did recall saying something along those lines, but that he couldn’t recall the exact circumstances. Doing my own due diligence (unlike the Mail!) the earliest reference I could find suggested that “the circumstances” involved a telephone interview much like the one I was in the middle of. In an article dated August 27th 2008 the Reuters environment correspondent reported that:

This year’s Arctic ice melt could surpass the extraordinary 2007 record low in the coming weeks. Last year’s minimum ice level was reached on September 16, according to the National Snow and Ice Data Center.

Even if no records are broken this year, the downward trend in summer sea ice in the Arctic continues, the Colorado-based center said. Last year’s record was blamed squarely on human-spurred climate change.

“No matter where we stand at the end of the melt season it’s just reinforcing this notion that Arctic ice is in its death spiral,” said Mark Serreze, a scientist at the center. The Arctic could be free of summer ice by 2030, Serreze said by telephone.

Mark confirmed to me that he still stood by his 2030 estimate for the onset of a seasonally ice free Arctic, although “most models say more like 2050”.

Next I asked him whether he agreed that “The Arctic sea ice spiral of death has reversed.” He said that he agreed with the statement attributed to Dr. Ed Hawkins near the end of the Mail article, that “There is undoubtedly some natural variability on top of the long-term downwards trend caused by the overall warming“. However 2 years worth of data certainly didn’t constitute “a recovery”. It was more like “a one week retracement in the US stock market. The long term trend in extent is definitely downwards”.

In conclusion I asked Mark to offer his best estimate for Arctic sea ice extent at this summer’s minimum. He told me that even at this late stage some of that “natural variability” could affect the outcome, but that the NSIDC extent “will probably end up on a par with 2013”.

I have also had an email conversation with Andrew Shepherd, the British “expert in climate satellite monitoring” whose views about Arctic sea ice were reported in the Mail on Sunday’s article. He told me that:

Arctic sea ice cover is expected to continue to decline, with the possibility of ice-free summers in the next 20-30 years. Climate model predictions tend to be at the upper end of this range, whereas projections of past observations tend to be at the lower end. Once we are able to include direct measurements of thickness from CryoSat-2, I expect the accuracy of predictions will improve.

If nothing else changes, then the recovery in Arctic sea ice thickness will wind the clock backwards a few years, but there is no reason to believe this is anything other than a temporary reprieve due to one cool summer.

Finally, for the moment at least, I also called the Danish Meteorological Institute. Along with the NSIDC their Arctic sea ice extent figures were quoted by David Rose. Along with the NSIDC they told me that they had received no enquiries recently from Mr. Rose or anyone else at the Mail on Sunday.